As is known, microwave ovens incorporate a magnetron as a microwave energy source feeding or propagating energy into a resonant cavity, with the food to be cooked being placed within the cavity. The feed system includes means for optimally coupling and distributing energy from the magnetron to the cavity. It is of course desirable to obtain a good energy distribution, or as commonly known in the trade a good cooking pattern, so as to minimize any "hot spots" or "cold spots" in the oven.
Various attempts have been made over the years to improve microwave ovens in the area of energy distribution. In some cases, the food was placed on a turntable rotating within the cavity having hot spots or cold spots in an attempt to average out these undesired zones during cooking. Many ovens now utilize a rotating element in the manner of rotating fan blades in the feed system. The blades have irregularly shaped surfaces, which when rotated, normally by a motor, scatter the microwave energy to all parts of the cavity.
However, the versatility of microwave ovens in being able to cook food of various sizes, shapes, dielectric properties, and in a variety of cooking containers, alters the energy distribution within the cavity. Thus, while various improvements based on principles of microwave energy distribution can be incorporated, the final results of such changes must be subjected to actual cooking tests to determine whether such changes have resulted in an improved energy distribution or cooking pattern.